1. Field of the Invention
The present invention relates to a hybrid integrated circuit device, and more particularly to a light irradiation device in which a plurality of light emitting elements are mounted.
2. Description of the Related Art
When a plant such as a flower or a vegetable is to be irradiated with a large amount of light, a device such as an electric lamp is usually used. In some cases, in order to reduce the size and weight of the device and the power consumption, a device in which light emitting elements 2 are mounted on a printed circuit board 1 as shown in FIG. 6 is used.
As the light emitting elements, light emitting diodes which are configured by semiconductor materials are mainly used. Alternatively, semiconductor lasers or the like may be used.
In each of the light emitting diodes 2, two leads 3 and 4 are used. The rear face (anode or cathode) of a light emitting diode chip 5 is fixed to the one lead 3 by soldering or the like. The other lead 4 is electrically connected via a thin metal wire 6 to an electrode (cathode or anode) on the surface of the chip. A transparent resin sealing member 7 which will serve as a lens is formed to seal the leads 3 and 4, the chip 5, and the thin metal wire 6.
On the other hand, electrodes 8 and 9 for supplying a power to the light emitting diode 2 are disposed on the printed circuit board 1. The leads are inserted into through holes opened in the electrodes. The light emitting diode 2 is mounted on the board via solder or the like.
A light irradiation device using such light emitting diodes is described in, for example, JP-A-9-252651.
As described above, the light emitting element 2 is configured by a package into which the resin sealing member 7, the leads 3 and 4, and the like are incorporated. When a large number of light emitting elements are mounted, therefore, there arise problems such as that the circuit board 1 is large in size and weight. Since the heat radiation properties of the circuit board itself are inferior, the circuit board has a problem in that the temperature of the whole device is excessively raised. Consequently, the temperatures of semiconductor chips themselves which constitute the light emitting elements are raised, thereby producing a problem in that the driving ability is lowered.
In the light emitting diode 2, light is emitted also from side and rear faces, and hence light directed toward the circuit board 1 exists. Since the circuit board 1 is configured by a printed circuit board, there is another problem in that irradiation of a high efficiency cannot be realized.
When such a light emitting element is mounted in the form of a bare shape, the light emitting element deteriorates, thereby producing a problem in that the amount of light is reduced and the light intensity is lowered. Furthermore, also a reflective plate formed on the printed circuit board is oxidized and there arises another problem in that the reflection efficiency is lowered.
The invention has been conducted in view of the above-discussed problems. An object of the invention is to provide a durable and reliable hybrid integrated circuit device.
First, the problems can be solved by a configuration which has a seal disposed in the periphery of a substrate, and a transparent substrate fixed via the seal.
Since a light emitting element and electrodes are disposed in a sealed space defined by the substrate, the transparent substrate, and the seal, deterioration of properties and oxidation can be prevented from occurring.
Second, the problems can be solved by a configuration comprising: a first electrode which is made of Cu covered with an oxidation resistant metal; a second electrode which is formed on another region of the substrate, and which is made of Cu covered with an oxidation resistant metal; a light emitting element in which a rear face of a chip is electrically fixed to the first electrode; connecting means for electrically connecting the second electrode to an electrode which is on a surface of the light emitting element; a seal which is disposed in a periphery of the substrate; and a transparent substrate which is fixed via the seal.
The second configuration functions in a similar manner as the first means. Particularly, the oxidation resistant films on the electrodes serve as light reflective films, and their glossiness also can be prevented from deteriorating.
Third, the problems can be solved by a configuration in which a plurality of hybrid integrated circuit substrates each of which has a seal disposed in the periphery of the substrate, and a transparent substrate fixed via the seal are arranged, and connecting means for electrically connecting the first and second electrodes on the hybrid integrated circuit substrates with one other is disposed.
In the configuration in which a transparent substrate is disposed for each of the hybrid integrated circuit substrates, even when a light emitting element is broken, each of the hybrid integrated circuit substrates can be independently repaired. When the arrangement angles of the hybrid integrated circuit substrates are adjusted, the substrates can be arranged in a convex or concave shape, so that light can be converged or diverged by the whole arrangement.
Fourth, the problems can be solved by a configuration in which a gas for preventing the light emitting element and/or the electrodes from deteriorating is filled into a space defined by the substrate, the transparent substrate, and the seal.
When the space is filled with nitrogen gas, an inert gas, or the like, deterioration of properties and oxidation of the electrodes can be further prevented from occurring.
Fifth, a spacer which is made of an insulating material is disposed inside the seal, whereby the transparent substrate can be mechanically supported. Even when, for example, the pressure of the space is lowered and the substrates are warped, the transparent substrate is supported, and hence prevented from being broken. Moreover, the thickness of the transparent substrate can be made smaller, so that absorption of light can be further reduced.
Sixth, a light transmitting resin which is formed into a lens-like shape is disposed in the light emitting element, whereby light emitted from the light emitting element can be converged.
Seventh, a top portion of the light transmitting resin abuts against the transparent substrate. According to this configuration, the spacer can be replaced with the resin. As compared with the case where a spacer is separately disposed, the area of the reflecting surface can be made larger.
Eighth, plural hybrid integrated circuit substrates are arranged in a matrix form, and at least end ones of the hybrid integrated circuit substrates are inclined at a predetermined angle with respect to a center one of the hybrid integrated circuit substrates. According to this configuration, it is possible to reflect light emitted in a direction which is substantially parallel to the hybrid integrated circuit substrates. Therefore, the amount of reflected light can be further increased.
Ninth, the seal is made of a glossy material, thereby enabling the seal to perform reflection.
Tenth, in the case where the seal is made of a resin, filling hole for the gas is formed in the seal, whereby the gas can be easily filled into the space, and the filling hole can be readily sealed.
As described above, when a substrate mainly made of Al is employed, particularly, it is possible to realize a light irradiation device which can attain excellent heat radiation properties, light weight, high workability, and improvement of performance, and which can be easily assembled and repaired. Moreover, the inclination can be set for each of the hybrid integrated circuit substrates. Therefore, a convex or concave face can be formed by the whole of the hybrid integrated circuit substrates, so that reflection of a high reflection efficiency can be realized.